Move FileManager code into libpbd. Use it for SMF read/write.

git-svn-id: svn://localhost/ardour2/branches/3.0@7108 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/pbd/pbd/debug.h

@@ -39,6 +39,7 @@ namespace PBD {
                 
                 extern uint64_t Stateful;
                 extern uint64_t Properties;
+		extern uint64_t FileManager;
 	}
 }
 

libs/pbd/pbd/file_manager.h

@@ -0,0 +1,149 @@
+/*
+    Copyright (C) 2010 Paul Davis
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef __pbd_file_manager_h__
+#define __pbd_file_manager_h__
+
+#include <sys/types.h>
+#include <string>
+#include <map>
+#include <sndfile.h>
+#include <glibmm/thread.h>
+#include "pbd/signals.h"
+
+namespace PBD {
+
+class FileManager;
+
+/** Parent class for FileDescriptors.
+ *
+ *  When a subclass is instantiated, the file it describes is added to a
+ *  list.  The FileDescriptor can be `allocated', meaning that its
+ *  file will be opened on the filesystem, and can then be `released'.
+ *  FileDescriptors are reference counted as they are allocated and
+ *  released.  When a descriptor's refcount is 0, the file on the
+ *  filesystem is eligible to be closed if necessary to free up file
+ *  handles for other files.
+ *
+ *  The upshot of all this is that Ardour can manage the number of
+ *  open files to stay within limits imposed by the operating system.
+ */
+	
+class FileDescriptor
+{
+public:
+	FileDescriptor (std::string const &, bool);
+	virtual ~FileDescriptor () {}
+
+	void release ();
+
+	/** Emitted when the file is closed */
+	PBD::Signal0<void> Closed;
+
+protected:
+
+	friend class FileManager;
+
+	/* These methods and variables must be called / accessed
+	   with a lock held on the FileManager's mutex
+	*/
+
+	/** @return false on success, true on failure */
+	virtual bool open () = 0;
+	virtual void close () = 0;
+	virtual bool is_open () const = 0;
+
+	int _refcount; ///< number of active users of this file
+	double _last_used; ///< monotonic time that this file was last allocated
+	std::string _name; ///< filename
+	bool _writeable; ///< true if it should be opened writeable, otherwise false
+
+	FileManager* manager ();
+	
+private:
+	
+	static FileManager* _manager;
+};
+
+/** FileDescriptor for a file to be opened using libsndfile */	
+class SndFileDescriptor : public FileDescriptor
+{
+public:
+	SndFileDescriptor (std::string const &, bool, SF_INFO *);
+	~SndFileDescriptor ();
+
+	SNDFILE* allocate ();
+
+private:	
+
+	friend class FileManager;
+
+	bool open ();
+	void close ();
+	bool is_open () const;
+
+	SNDFILE* _sndfile; ///< SNDFILE* pointer, or 0 if the file is closed
+	SF_INFO* _info; ///< libsndfile's info for this file
+};
+
+/** FileDescriptor for a file to be opened using POSIX open */	
+class FdFileDescriptor : public FileDescriptor
+{
+public:
+	FdFileDescriptor (std::string const &, bool, mode_t);
+	~FdFileDescriptor ();
+
+	int allocate ();
+
+private:
+
+	friend class FileManager;
+
+	bool open ();
+	void close ();
+	bool is_open () const;
+
+	int _fd; ///< file descriptor, or -1 if the file is closed
+	mode_t _mode; ///< mode to use when creating files
+};
+
+/** FileDescriptor for a file opened using stdio */
+class StdioFileDescriptor : public FileDescriptor
+{
+public:
+	StdioFileDescriptor (std::string const &, std::string const &);
+	~StdioFileDescriptor ();
+
+	FILE* allocate ();
+
+private:
+
+	friend class FileManager;
+
+	bool open ();
+	void close ();
+	bool is_open () const;
+
+	FILE* _file;
+	std::string _mode;
+};
+
+}
+
+#endif